It looks like a record, but it's not exactly a record. It spins at 33 &1/3 rpm like a record but it's about 16" in diameter, that's 4 inches wider than your record crates, but could only hold about 15 minutes of audio per side. But the upside was the audio quality was better than a 78.
It was the year 1929. The great depression changed everything. Leisure items became luxury goods. Thomas Edison's cylinders and discs ceased production entirely. Conglomerates bought up smaller failing independents. Mass production made possible the reduced price of LPs of all kinds. And for radio stations the ability to replay programs was a huge cost-saver.
In 1929 RCA/Victor began making discs from "Vitrolac" (the precursor to vinyl.) It was picked up as a professional medium for radio transcription discs and the Library of Congress also used Vitrolac for talking books for the blind.
Two years later they took that magic material and introduced a type of long-playing record that allowed long form radio programs to fit on a manageable number of discs. These records held between double and triple the amount of music as a standard 78rpm disc. RCA's long-playing format apparently did not catch on. Introducing it in the middle of the Depression cannot have helped.
Prior to the vitrolac disc, the primary purpose of the aluminum disc was for advertiser program reviews. The aluminum discs were only good for a couple plays. Previous to this there were only aluminum transcription discs. These could only be played with a bamboo needle and in fact would be destroyed by a traditional steel needle. In Instead of aluminum discs, the RCA system used recording blanks made of a plastic material, either solid or bonded to a cardboard core. RCA issued blanks with pre-cut grooves which guided the tone arm along the surface of the disc. It was big improvement over the groove-less aluminum blanks.
By 1931 RCA was trying to market these discs to consumers but the idea was a bust. Consumers didn't like the 33 & 1/3 playing speed. But as a commercial product it stuck. The professional transcription disc the standard transcription disc for radio station recording until magnetic tape gained dominance around 1948.
Transcription discs probably peaked 942-1946 when AFRN (Armed Forces Radio Network) was created to distribute programs to soldiers overseas. By January 1946, 1030 vinylite 16-inch transcription discs of 8240 popular and classical songs had been produced as part of the Basic Music Library for the AFRN.
In the middle of this, the head of the American Federation of Musicians, James C. Petrillo, banned the use of transcriptions, insisting that all radio shows be performed live. This begat a musicians' strike that dragged all the way into 1945! ...But that's another story...